Wednesday, April 29, 2009

I'm doing this month's carnival a bit differently. Instead of blogs sending in their own posts, I'm venturing out and choosing some of my favorite blogs and articles. Each month, I'll choose 10 or so articles for you to read. Let me know what you think of the new format!

Whilst the creatures can clearly be seen to react to a jab or blow, experts have disagreed over whether the reaction indicates a sensation of pain, or is little more than a basic reflex.

Researchers set out to establish the truth with an experiment in which goldfish were exposed to painful heat. Half of the fish were given a painkilling injection of morphine beforehand, while the other half were not.

Two hours later, the fish that had undergone the test without painkillers showed signs of fear and wariness – suggesting, say the researchers, that they had suffered a bad experience and remembered it.

The academics, from Norway and the US, say their finding undermines claims that fish merely display reflex actions and do not sense pain.

"The results show that it could not have been a simple reflex action," said Dr Joseph Garner.

"The fact that their behaviour changed so much really strongly suggests there is something going on with their memory and experience of that event that is not a reflex. I believe it does show that fish feel pain."

For the experiment, each fish was fitted with a miniature jacket containing a tiny flexible foil heater similar to those used in the aerospace industry to keep wires and electrics dry. The heaters had an upper safety limit of 50C to prevent harm.

Both groups of fish – those given morphine, and the control group which were injected with inactive saline solution – showed a similar "escape response" when the heater was turned up to around 38C, equivalent to a fairly hot bath.

As soon as the behaviour was noted, the heat was turned off to prevent suffering.

An escape response consisted of curling the body or flicking the tail in a way that would have propelled the fish away had its movements not been restricted.

However, the difference between the groups emerged after the fish had been returned to their normal home tanks. Two hours later, it was the fish which had not been given morphine which were more likely to display fearful behaviour such as "hovering".

Wednesday, April 22, 2009

On May 26, 2009 the NIH Pain Consortium will host its Fourth Annual Symposium. Each year this symposium features presentations by NIH supported researchers whose work has made a significant contribution to the field of pain research.

The theme of this year's symposium will be genetics and pain. Topics will include human genetic risk factors for chronic pain, genes relevant to treatment response and abuse potential, and genetic tools and models for pain research. A poster session will include a broad selection of current pain research findings presented by young investigators. Members of the extramural scientific community, the NIH scientific community, health care providers, and the public are invited to attend. The event will be hosted by the co-chairs of the NIH Pain Consortium.

Monday, April 20, 2009

In the moments after I felt the pop in my left shoulder, the sensation I felt was not pain. It was panic. How exactly does a 40-year-old man explain to his wife that he might have torn his rotator cuff during a midnight game of Wii tennis?

Dr. Charles Young made me feel better without even examining me.

Late last year, Dr. Young, an orthopedic surgeon, spent about an hour experimenting with the balance games and strength-training exercises on his new Wii Fit. Running on a virtual trail. Slalom skiing. Walking on a tightrope. "They have this hula-hoop one where you're supposed to spin yourself in a circle and try to get a high score," said Dr. Young, who is completing a sports medicine fellowship at the Cleveland Clinic. "I was really hurting."

In the operating room the next day he commiserated with several nurses who confessed that they had, at least figuratively, already felt his pain.

To say that Wii injuries are an epidemic would be an overstatement, but they are proliferating along with the popular video-game system. Interviews with orthopedists and sports medicine physicians revealed few serious injuries, but rather a phenomenon more closely resembling a spreading national ache: patients of all ages complaining of strains and swelling related to their use — and overuse — of the Wii.

Call it Wii Shoulder. Or Wii Knee. If there is an epidemic of anything, it probably falls under a broader label: Nintendinitis.

"Skateboarding, snowboarding, you name it," said Dr. William N. Levine, the director of sports medicine at NewYork-Presbyterian Hospital/Columbia University Medical Center. "Take the newest fad, and there's always a slew of specific orthopedic injuries associated with it."

The difference now is that the surging sales of the Wii system mean that misery gets more company every day. Nintendo, which introduced the Wii in November 2006, sold more than 10 million of the game systems in the United States last year, including a record 2.1 million in December. The complementary Wii Fit exercise program has been nearly as popular, with more than 6.5 million sold since its introduction last May.

Consumers who avoided sedentary video-game systems have flocked to the Wii, which lures users off the couch with a handheld, wireless remote and a selection of familiar, free-swinging games like tennis, boxing and bowling. For some parents, and even grandparents, the games are a way to connect with children on their own turf. The fact that everyone gets a little exercise along the way is an added plus.

"It's great in the concept that it gets people active and involved," said Dr. Brian Halpern, a sports medicine physician at the Hospital for Special Surgery in Manhattan. "It's not great in that you get lost in that and are overloading areas that you haven't worked out in a long time, if ever."

Dr. Halpern said he had treated two types of injuries: traumatic injuries like twisted knees and sprained ankles from playing the games in confined spaces, and repetitive stress problems from playing too long. A common problem is the realization by players that a full swing is not required; a flick of the wrist is often enough to return a serve or bowl a strike. As several doctors pointed out, that is the exact motion — concentrating the force of a swing in the muscles of the forearm — that can cause tennis elbow.

The Wii system was built with warnings about prolonged use, and electronic prompts interrupt players regularly to urge them to take a break.

Denise Kaigler, a vice president for marketing and corporate affairs at Nintendo of America, said in an e-mail message that "as consumers adapt to this new style of play, there have been a few reports of minor incidents during overly enthusiastic game play," but that more health and safety warnings — about playing in an area free of obstructions, for example — had been added.

"As with any new activity, people playing the Wii system should pace themselves and not overdo it," Ms. Kaigler said.

Dr. John Sperling, a physician at the Mayo Clinic in Rochester, Minn., called the aches and pains a sign of the times. "It's a syndrome of injuries and people presenting with complaints that we couldn't have imagined three years ago," he said.

Dr. Levine said the youngest patient he had treated was 12. Dr. Young, who overworked his core muscles using the Wii Fit, is 32. Dr. Sperling's patients have included a 22-year-old whose arm swelled to twice its size after a marathon Wii session, and a man in his 60s.

"I was asking him what happened," Dr. Sperling said of the older patient, "and he said, 'Well, we bought a Wii system for the grandkids. Next thing I know, my shoulder's killing me.' "

Dr. Halpern, a former assistant team physician for the Mets, compared some Wii injuries to those sustained by professional athletes.

"It's like if you have a pitcher who has gone to spring training and hasn't worked hard in the off-season and starts throwing too much and kind of overloads his shoulder or elbow," he said.

And just as that pitcher might have to take several days off, a person experiencing pain from a session of Wii games should do the same. While "the rush of beating kids a fraction of your age in Wii Sports far outweighs the discomforts of getting older," Ms. Kaigler said, moderation is just as important. That may be especially true for older players.

My shoulder recovered with time away from the Wii, not a problem in a household with three children who were all eager to play and who are apparently more durable than their father. The lasting image of Christmas at my family's home was that of my 5-year-old daughter in a velvet dress, blond hair tucked behind one ear, raining punches on a hulking man with a goatee. She knocked him out, but quickly moved on to baseball and bowling and golf.

Dr. Halpern said the shorter attention spans of younger children were probably preventing them from developing overuse injuries, describing their exposure to a variety of Wii games as "cross-training without even thinking about it." Sore-shouldered and gimpy-kneed adults could be victims of their better focus, but also of their innate competitiveness.

"It's good to be a kid at heart," said Dr. Susan Joy, the director of the Cleveland Clinic's women's sports health program. "But sometimes when you start a new exercise program, it's good to remember that you're not a kid."

This booklet has been written to help you understand the nature of chronic pain and to assist you to find the best advice and treatment. You are not alone in suffering chronic pain. Everybody experiences short term pain from time to time, but there are surprisingly many people, like yourself, who have experienced pain over a long period with little or no relief.

Over the last decade or so there have been many advances in the world of medicine. Unfortunately, there are still no specific 'cures' for many types of chronic pain. We do, however, have several treatments which may offer partial relief (and in some cases complete relief), and certain treatments which are only available from health professionals who have particular skills in the treatment of chronic pain.

Pain is a complex individual experience with sensory, emotional and social aspects. It is important to understand that no two people will experience the same pain in the same way. This is because the messages that pain gives to our brain may not be interpreted by one person in the same way as another person, and because our individual experience of life colours the way we experience and express our pain.

We intend that this short booklet be of some help to you in understanding the nature of your pain problem, and hope that it may aid in your search for a measure of relief.

Saturday, April 18, 2009

A drug commonly used to treat heroin addiction appears to ease thesymptoms of fibromyalgia, a poorly understood but potentiallydebilitating condition that affects up to 12 million people in theU.S. (4 percent of the population), a small pilot study has found.

"We have a medication that seems to have low side effects and seemsto reduce pain and fatigue [in fibromyalgia patients]," says JarredYounger, a pain researcher at Stanford University School of Medicineand co-author of the study appearing today in Pain Medicine. "I thinkthis is a potential treatment to add to the doctor's arsenal," headds, noting that longer studies involving more patients are neededto confirm the results.

Fibromyalgia, a mysterious ailment whose symptoms include chronicwidespread muscle pain, fatigue, sleep problems, anxiety anddepression, often appears between the ages of 34 and 53 and is morecommon in women (affecting 5 percent of women and 1.6 percent of menin the U.S.), the researchers report. The U.S. Food and DrugAdministration (FDA) has approved three drugs for treatingfibromyalgia, but many patients don't respond to them, Younger says.

For 14 weeks, Younger and his colleague Sean Mackey, chief of thepain management division at Stanford, monitored the symptoms of 10women ages 22 to 55 with fibromyalgia before, during and after theytook small doses (4.5 milligrams per day) of naltrexone, a drug thatfor about three decades has been used to wean addicts off of heroinand other street drugs. (Naltrexone works by latching onto nerve cellreceptors where heroin and other opioid drugs would dock, thusblocking their ability to act on the cells and induce a feeling ofbeing high.) Using handheld computers, the women reported theseverity of their daily symptoms on a scale of one to 100 (100 beingthe most severe). Every two weeks, they visited the researchers whodownloaded the data entered in the computers and ran tests to measurethe women's pain thresholds for pressure, heat and cold applied tothe skin.

Their findings: the severity of pain and fatigue fell by 30 percentduring the weeks the women were taking naltrexone compared with thosein which they were taking a placebo. Two of the women said the druggave them vivid dreams and one said she had nausea and insomnia thefirst few nights that she took the pills, but otherwise no sideeffects were reported.

Younger, who suspects fibromyalgia is an autoimmune disorder (inwhich the body's immune system attacks healthy tissue), speculatesthat naltrexone is alleviating fibromyalgia symptoms not by blockingnerve cell receptors but by dampening the activity of microglia—immune cells in the brain and spinal cord that produce pro-inflammatory cytokines, which excite nerve cells responsible forcreating the sensation of pain.

"These results are promising," says Dan Clauw, an anesthesiologist atthe University of Michigan at Ann Arbor's Chronic Pain & FatigueResearch Center who was not involved with the study. But Clauw is notconvinced that naltrexone works by suppressing immune cells; hethinks low doses of the drug might stimulate nerve cells to releasepain-alleviating endorphins.

Regardless of how the drug works, the scientists agree that moreresearch is needed to confirm these preliminary findings. TheStanford team is already about two thirds of the way through a 24-week follow-up study involving 40 patients. And although Youngerhasn't started analyzing the data, he says, "The participants seemhappy…I think it looks good."

Sunday, April 05, 2009

As a former competitive cyclist, University of Illinois kinesiology and community health professor Robert Motl routinely met his teammates at a coffee shop to fuel up on caffeine prior to hitting the pavement on long-distance training rides.

"The notion was that caffeine was helping us train harder … to push ourselves a little harder," he said.

The cyclists didn't know why it helped, they just knew it was effective.

"I think intuitively a lot of people are taking caffeine before a workout and they don't realize the actual benefit they're experiencing. That is, they're experiencing less pain during the workout," Motl said.

He said it's becoming increasingly common for athletes – before competing – to consume a variety of substances that include caffeine, motivated by "the notion that it will help you metabolize fat more readily."

"That research isn't actually very compelling," Motl said. "What's going on in my mind is … people are doing it for that reason, but they actually take that substance that has caffeine and they can push themselves harder. It doesn't hurt as much."

The U. of I. professor has been investigating the relationship between caffeine and physical activity since taking a slight detour during his doctoral-student days, when his work initially was focused on exploring possible links between caffeine intake, spinal reflexes and physical activity.

Seven years later, with several studies considering the relationship between physical activity and caffeine behind him, Motl has a much better understanding of why that cuppa Joe he used to consume before distance training and competing enhanced his cycling ability.

Early in his research, he became aware that "caffeine works on the adenosine neuromodulatory system in the brain and spinal cord, and this system is heavily involved in nociception and pain processing." Since Motl knew caffeine blocks adenosine from working, he speculated that it could reduce pain.

A number of studies by the U. of I. professor support that conclusion, including investigations considering such variables as exercise intensity, dose of caffeine, anxiety sensitivity and gender.

Motl's latest published study on the effects of caffeine on pain during exercise appears in the April edition of the International Journal of Sport Nutrition and Exercise Metabolism.

"This study looks at the effects of caffeine on muscle pain during high-intensity exercise as a function of habitual caffeine use," he said. "No one has examined that before.

"What we saw is something we didn't expect: caffeine-naïve individuals and habitual users have the same amount of reduction in pain during exercise after caffeine (consumption)."

The study's 25 participants were fit, college-aged males divided into two distinct groups: subjects whose everyday caffeine consumption was extremely low to non-existent, and those with an average caffeine intake of about 400 milligrams a day, the equivalent of three to four cups of coffee.

After completing an initial exercise test in the lab on an ergometer, or stationary cycle, for determination of maximal oxygen consumption or aerobic power, subjects returned for two monitored high-intensity, 30-minute exercise sessions.

An hour prior to each session, cyclists – who had been instructed not to consume caffeine during the prior 24-hour period – were given a pill. On one occasion, it contained a dose of caffeine measuring 5 milligrams per kilogram of body weight (equivalent to two to three cups of coffee); the other time, they received a placebo.

During both exercise periods, subjects' perceptions of quadriceps muscle pain was recorded at regular intervals, along with data on oxygen consumption, heart rate and work rate.

"What's interesting," Motl said, "is that when we found that caffeine tolerance doesn't matter, we were perplexed at first. Then we looked at reviews of the literature relative to caffeine and tolerance effects across a variety of other stimuli. Sometimes you see them, sometimes you don't. That is, sometimes regular caffeine use is associated with a smaller response, whereas, other times, it's not."

No one's been able to figure out the reason for the inconsistency, Motl said.

"Clearly, if you regularly consume caffeine, you have to have more to have that bigger, mental-energy effect. But the tolerance effect is not ubiquitous across all stimuli. Even brain metabolism doesn't show this tolerance-type effect. That is, with individuals who are habitual users versus non-habitual users, if you give them caffeine and do brain imaging, the activation is identical. It's really interesting why some processes show tolerance and others don't."

Regarding the outcome of the current research, he said, "it may just be that pain during exercise doesn't show tolerance effects to caffeine."

Motl said one of the next logical steps for his research team would be to conduct studies with rodents in order to better understand the biological mechanism for caffeine in reducing pain.

"If we can get at the biological mechanism, we can begin to understand why there may or may not be this kind of tolerance."

Motl said another research direction might be to determine caffeine's effect on sport performance.

"We've shown that caffeine reduces pain reliably, consistently during cycling, across different intensities, across different people, different characteristics. But does that reduction in pain translate into an improvement in sport performance?"

Meanwhile, the current research could prove encouraging for a range of people, including the average person who wants to become more physically active to realize the health benefits.

"One of the things that may be a practical application, is if you go to the gym and you exercise and it hurts, you may be prone to stop doing that because pain is an aversive stimulus that tells you to withdraw. So if we could give people a little caffeine and reduce the amount of pain they're experiencing, maybe that would help them stick with that exercise.

"Maybe then they'll push a little harder as well … maybe get even better adaptations to the exercise."

Everyone knows what pain is - from giving birth, a stubbed toe, an infected tooth, a burn, surgery or a fall - and the physiological mechanism is well understood. But chronic pain, from which nearly 20 percent of the population suffer - migraines, rheumatic disease, cancer, neuropathy, "phantom limb" syndrome, spinal problems and others - is considered a fully fledged "illness" in addition to the pathologies that cause it.

Pain is one of the most persistent health problems faced by humanity. Although chronic pain itself is not life-threatening, it can lead to depression and suicide.

Unfortunately, the mechanism involved in chronic pain is still not completely understood and thus it's not preventible or curable, but neuroscientists like Hebrew University Prof. Marshal Devor continue to make progress in trying to find answers. He has come to one big conclusion - that specific genes determine why two patients with exactly the same stage of the same disease may experience different amounts of pain. This variability from one person to the next is a major puzzle.

Prof. Marshall Devor, 60, who was born in Toronto and studied at Princeton and MIT, came on aliya 30 years ago. Today he works in the department of cell and animal biology at HU's Institute of Life Sciences, and his lab has published extensively on pain, neurophysiology, neuroanatomy, genetics and animal behavior.

THE VARIABILITY in the sensation of acute pain, says Devor, is clear when a slap in the face that provokes sobs in one person is laughed off by another. Every individual has a different pain threshold, and variability in expression has also been attributed to cultural and psychosocial factors such as personality and upbringing. Women in one country may scream in delivery rooms while those in another are silent. In some countries, he notes, people "don't hesitate to express their pain, while in others, children are taught to be stoical. There are also big differences between men and women, girls and boys... Is it possible that the socialization of boys and girls actually alters the amount of pain experienced, and not just how pain is expressed?"

Devor stresses that pain cannot be shared. "Pain is inherently a private, first-person sensory and emotional experience. It is felt by the person; even using delicate instruments, a doctor cannot know exactly how intense is the suffering of a victim; he can only observe outward behavior and language." However, pain can be measured subjectively by sufferers on a scale of 0 to 10. Children can describe the amount of pain they feel using a graphic scale of faces. Animals can feel pain, says Devor, and can be judged by their reactions such as pulling a paw away.

Advances in non-invasive brain imaging such as functional magnetic resonance imaging (fMRI) or positron emission tomography (PET) may soon make it possible to know objectively whether someone is faking or exaggerating his pain; the amount of neural activity, he says, rises and falls in certain parts of the brain to reflect the amount of pain, but the amount of pain felt can be changed by hypnosis, pain- killing drugs and even anticipation. One can also observe signals indicating that a loved one of the person you are testing is in pain. "Just knowing that a loved one is suffering affects your own brain, and you can see such empathy in monkeys and even mice."

Pain, he adds, "is both friend and foe. Acute pain is for the most part a friend, as it warns of a problem; but if a part of torture, such pain is of course a foe." Chronic pain is a foe as well, and while it is defined as suffering that lasts at least six months, the average is at least four years.

Pain "resides at the interface of body and mind; only people who are conscious can feel pain." It has been defined by pain experts as "an unpleasant sensory and emotional experience associated with actual or potential tissues damage, or described in terms of such damage."

Neurons in the spine, explains Devor, have long axons. A stimulus generates electrical impulses, and the signal goes into various parts of the cerebral cortex and other brain regions called the pain matrix. The stimulus affects specific patches of brain cells. Scientists don't know how pain is experienced in the brain. It is initiated by physical stimuli translated into electrical signals, the neuroscientist continues, "but if you stimulate nerve fibers electrically along the path, a person will say he feels a sensation, not in the nerve but in his hand, for example. If a nerve is injured, or you have a viral infection or inflammation, the injury site becomes an abnormal source of electrical impulses. They run to the brain and are perceived there."

Phantom limb pain is very puzzling. If a hand or arm has been amputated or lost - as happened to Admiral Lord Nelson (who died in the 1805 Battle of Trafalgar) - one can still feel pain in the missing part. The brain sends signals down the spinal cord, causing the victim to feel pain without the signal reaching the limb.

ONE CAN also be seriously injured without feeling pain: Devor describes a drawing from the Battle of Handak, which involved a schism between Shi'ite and Sunni Muslims. The leg of a soldier in the battle was severed and he goes on to use his limb as a weapon, as he feels no pain. This phenomenon has also been documented in people who suffer severe injuries in road accidents. Animals too can suppress pain caused by sudden events. This is called stress-induced neuralgia.

One's expectations also affect pain perception. If one goes to a non- medical "healer" who waves his hands above your body or ties a red string around your wrist, or to a clergyman who gives you a blessing, these can relieve pain, Devor says. Faith and superstition can actually relieve pain. "The belief that a red string will relieve pain can actually relieve pain. It's called placebo analgesia, and it's real and sometimes powerful. It could even be as effective as an injection of morphine." This ability, he suggests, "was given to the brain to suppress pain in times of emergency. It is endogenous, designed to let the body fight and struggle, and lick the pains later. It is brain circuitry of relief."

An experiment was conducted to allow Christian subjects to meditate on either of two photos - an ordinary woman and the Virgin Mary. The images look similar, and the subjects were either devout Catholics or atheists. Both were then exposed to a heat stimulus. The image of Mary had no pain-relieving effect in the non-believer group, but it did relieve pain in the devout, recalls Devor.

He notes that for many years, pediatricians and parents were unaware that newborn infants felt pain because they thought their nervous systems were still undeveloped - or that they wouldn't remember it anyway. For that reason, when painful procedures were conducted, no analgesia was offered. But more recent studies have shown that newborns are indeed capable of feeling pain, and not giving anesthesia before a painful procedure is now considered a form of abuse.

"We don't know how much newborns remember pain or for how long, but an Israeli study showed that eight-year-old boys who have been circumcised cry much more than girls after they get childhood vaccinations."

IN ADDITION to socialization and other psychosocial and environmental factors, says Devor, differences in the wiring of our individual brains due to gene variations are responsible for how people respond to pain.

Rare familial diseases inherited by some people but not by others give good evidence of this, as have identical-twin studies. More recently, scientists have been identifying specific genes that make it more likely that one will suffer pain in response to injury or disease, says the neuroscientist.

New knowledge of how genes affect pain could not only lead to improved pain relief but also eliminate the stigma of being a "crybaby" in people who say their condition is more unbearable than that suffered by others with the same disease; the difference can be explained by their DNA.

Not all 25,000 genes in each cell affect pain sensation, he says. "For some genes, however, there are rare variants [mutations] or common variants [polymorphisms] that do affect the functioning of the proteins encoded... At present, we have no idea how many genes" affect pain response. Some pain genes may have no effect on pain at all except under unusual circumstances, Devor says, such as at high altidues or if your sister-in-law made you particularly exasperated. In this case, the genes' influence interacts with the environment. Certain pain relievers such as opiods, he concludes, relieve pain in one sex or another.

"The genetic revolution has only just started to affect the field of pain science and medicine. There is well-founded optimism abut the potential power of linkage analysis and association studies... The payoff in terms of new therapeutic options is likely to be not too far down the road. That is certainly good news for the one in five prople who suffer from chronic pain."

Wednesday, April 01, 2009

Dr. Hershel Samuels, an orthopedic surgeon, put his hand on the worker's back. "Mild spasm bilaterally," he said softly. He pressed his fingers gingerly against the side of the man's neck. "The left cervical is tender," he said, "even to light palpation."

The worker, a driver for a plumbing company, told the doctor he had fallen, banging up his back, shoulder and ribs. He was seeking expanded workers' compensation benefits because he no longer felt he could do his job.

Dr. Samuels, an independent medical examiner in the state workers' compensation system, seemed to agree. As he moved about a scuffed Brooklyn office last April, he called out test results indicative of an injured man. His words were captured on videotape.

Yet the report Dr. Samuels later submitted to the New York State Workers' Compensation Board cleared the driver for work and told a far different story: no back spasms, no tender neck. In fact, no recent injury at all.

"If you did a truly pure report," he said later in an interview, "you'd be out on your ears and the insurers wouldn't pay for it. You have to give them what they want, or you're in Florida. That's the game, baby."

Independent medical exams are among the most disputed components of New York's troubled workers' compensation system. Under that system, workers with bona fide injuries are entitled to medical care and replacement wages, usually paid for by their employer's insurer.